FYI, you should start seeing a new metric in your test results - DOM Elements. It is the count of elements on your document (and any documents within iFrames). It's useful for getting an idea for how complex your page is and should be really interesting to watch over time (and in aggregate).

Let me know if you see it not behaving well. I did some spot checks comparing it against document.getElementsByTagName("*").length on pages without iFrames and it looked about right.

Right now it's only available in the IE agents - should be coming to Chrome shortly.